This invention relates generally to a protective construction for a pointed end of a medical needle of the type used to pierce the tissue of a patient to inject or withdraw fluid from such patient. More particularly, the present invention is directed to such a construction having a protective sheath which automatically covers the pointed end of the needle when it is extracted from a patient.
Many infectious diseases may be transmitted through an accidental puncture by a contaminated medical needle. This problem is particularly acute with disposable hypodermic needles since they are not sterilized after use and often are not disposed in a manner which will reduce the likelihood of accidental puncture. Since the event of Acquired Immune Deficiency Syndrome (AIDS), increasing concern has developed on the subject of the safety of hypodermic needles.
There have been many designs for shielding the pointed end of a hypodermic needle after use. Many involve manual manipulation to recap the pointed end--some are automatic and thus do not require manual manipulation. Manual capping of a hypodermic needle has many disadvantages. For example, the more one has to manipulate a needle point, the higher the risk of accidental injury. In this connection, with some designs the recapping operation itself can result in an accidental puncture. Moreover, manual manipulation is time consuming. In today's medical environment in which health care workers are already overworked and short in supply, the time spent in recapping a hypodermic needle can be much better utilized on other tasks. Considering the number of times a hypodermic needle is used, the total time spent on recapping hypodermic needles is quite significant. In a sense, that represents an inefficient use of resource. Examples of prior designs which require manual manipulation are described in U.S. Pat. Nos. 3,406,687; 4,681,567; 4,747,837; and 4,801,295.
Past automatic designs, on the other hand, generally are complicated, costly to manufacture, and/or prone to defects. As a general rule, the more complex the design, the more expensive the cost of manufacturing, and the more likely it is that the construction will malfunction. An example of an automatic design is described in U.S. Pat. No. 4,775,369.
Some of the above identified problems of automatic type hypodermic needle protective designs are also applicable to those designs requiring manual manipulation. There is much room for improvement. This invention is directed to a substantial improvement in the design of protective constructions for medical needles to reduce the incidence of accidental needle stick injuries.